More and more devices are being replaced with autonomous and semiautonomous electronic devices. This is especially true in the hospitals of today with large arrays of autonomous and semiautonomous electronic devices being found in operating rooms, interventional suites, intensive care wards, emergency rooms, and the like. For example, glass and mercury thermometers are being replaced with electronic thermometers, intravenous drip lines now include electronic monitors and flow regulators, and traditional hand-held surgical instruments are being replaced by computer-assisted medical devices.
These electronic devices provide both advantages and challenges to the personnel operating them. Many of these electronic devices may be capable of autonomous or semi-autonomous motion of one or more articulated arms and/or end effectors. These one or more articulated arms and/or end effectors each include a combination of links and articulated joints that support motion of the articulated arms and/or end effectors. In many cases, the articulated joints are manipulated to obtain a desired position and/or orientation (collectively, a desired pose) of a corresponding tool located at a distal end of the links and articulated joints of a corresponding articulated arm and/or end effector. Each of the articulated joints proximal to the tool provides the corresponding articulated arm and/or end effector with at least one degree of freedom that may be used to manipulate the position and/or orientation of the corresponding tool. In many cases, the corresponding articulated arms and/or end effectors may include at least six degrees of freedom that allow for controlling a x, y, and z position of the corresponding tool as well as a roll, pitch, and yaw orientation of the corresponding tool. To provide for greater flexibility in control of the pose of the corresponding tool, the corresponding articulated arms and/or end effectors are often designed to include redundant degrees of freedom. When redundant degrees of freedom are present it is possible that multiple different combinations of positions and/or orientations of the articulated joints may be used to obtain the same pose of the corresponding tool. This creates a null space where even though the articulated joints are moving, the pose of the corresponding tool is not.
As each of the articulated arms and/or end effectors is being operated, the articulated arm and/or end effector may be subject to motion, both planned and unplanned, that may result in movement in one or more of the articulated joints. As this motion changes the positions and/or orientations of the one or more articulated joints, the changes may introduce undesirable alteration to the pose of a tool being manipulated by the articulated arm. This alteration to the pose may result in injury to a patient, injury to personnel in proximity to the articulated arms and/or end effectors, damage to the articulated arms and/or end effectors, damage to other devices in proximity to the articulated arms and/or end effectors, breach of a sterile field, and/or other undesirable outcomes.
Accordingly, it would be desirable to maintain a pose of a tool in the presence of disturbances in articulated joints located proximal to the tool.